CVE-2021-27239
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400 and R6700 firmware version 1.0.4.98 routers.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.77%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400 and R6700 firmware version 1.0.4.98 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the upnpd service, which listens on UDP port 1900 by default. A crafted MX header field in an SSDP message can trigger an overflow of a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-11851.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.77% probability · 55th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-121
- Affected
- netgear/d6220 firmware · netgear/d6400 firmware · netgear/d7000 firmware · netgear/d8500 firmware · netgear/dc112a firmware · netgear/ex7000 firmware · netgear/ex7500 firmware · netgear/r6250 firmware · netgear/r6300 firmware · netgear/r6400 firmware · netgear/r6700 firmware · netgear/r6900p firmware · netgear/r7000 firmware · netgear/r7000p firmware · netgear/r7100lg firmware · netgear/r7850 firmware · netgear/r7900 firmware · netgear/r7900p firmware · netgear/r7960p firmware · netgear/r8000 firmware · +15 more
- Source
- zdi-disclosures@trendmicro.com
EPSS 0.8% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://kb.netgear.com/000062820/Security-Advisory-for-Stack-based-Buffer-Overflow-Remote-Code-Execution-Vulnerability-on-Some-Routers-PSV-2020-0432Vendor Advisory
- https://www.zerodayinitiative.com/advisories/ZDI-21-206/Third Party Advisory, VDB Entry
- https://kb.netgear.com/000062820/Security-Advisory-for-Stack-based-Buffer-Overflow-Remote-Code-Execution-Vulnerability-on-Some-Routers-PSV-2020-0432Vendor Advisory
- https://www.zerodayinitiative.com/advisories/ZDI-21-206/Third Party Advisory, VDB Entry
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.